The present invention relates to fluid control valves of the type having a body, a valve member which is movable inside a chamber in the housing, and a gasket for sealing between the body and the valve member.
Valves of this type can be used whenever it is desired to block the flow of a fluid under pressure; to cause it to flow through an outlet port; or to have the fluid itself be led in a particular direction for use in a plurality of arrangements in series. This latter situation is the case for all devices used for controlling the energy of the fluid, such as for example shut-off valves, three-way, four-way, or five-way valves. Such devices are generally constructed with the use of spool systems (consequently with sliding gasket) or with the use of closure elements of various sorts. In all these last-named devices, the closing operation is brought about by means of a force acting on the gasket. This creates initially the conditions suited for sealing which require a certain compression between the valve element and the gasket and thereafter the maintaining of the seal and blocking of the hydraulic fluid. This force is therefore equal to the sum of a force which along the sealing surface has a greater pressure as does the pressure of the fluid to be held back and a force which is proportional to the pressure and to the surface upon which it acts.
The contact pressure leads to a rapid wearing of the gasket and also of the valve element. To this is added a recess which often leads to sealing difficulties, since the action of the sealing edge or seat of the body on the gasket can become eccentric with respect to such a recess already there, with the resulting conditions for a complete sealing being rather precarious.
It is therefore an object of the invention to avoid these problems of the wear of the seat and the recess and to provide a control apparatus in which the necessary force for the closing and the blocking of the fluid is minimized, so that such arrangements can also be utilized in the miniaturization of pressurized fluid systems, especially logic systems.